'93 300 SE hard hot-start >>> HELP?

[krasuskyp]

My bro's '93 300SE with ~ 140k has developed a hard hot(ish) start issue, hoping someone out here can point me in right direction.

Basically, here's what it's doing:

- 1st start in a.m. is fine
-5 minute to 4 hour or so sitting, starts fine
-7-9 hour sitting, car cranks and cranks, finally starts, runs fine
-12-24 hours, starts fine

Any insight greatly appreciated. Of course, car starts acting up as bro is over in da Desert and his wife is left with car that suddenly wants to misbehave! Typical.

Thanks!